Remote-control system



Nov. 4, 1947. H. G. EVERS REMOTE CONTROL SYSTEM Original Filed Aug. 25, 1944 3 Sheets-Sheet 1 wil REGISTER RELAYS CONTROL DEVICE CONTROL DEVICE LQQ INVENTOR. HARRY G. EVERS ATTORNEY Nov. 4, 1947.

H. G. EVERS' REMOTE CONTROL SYSTEM Original Filed Aug. 5, 1944 3 Sheets-Sheet 2 RECEIVER R o m n n Fl mu m w M N m EA A. m 4 v5 6 7 O 3 w w W INVENTOR. HARRY G. EVERS ATTORNEY Nov. 4, 1947.

H. G. EYERS REMOTE CONTROL SYSTEM A Original Filed Aug; 5, 1944 s Sheets-Sheet 5 965v HI! vac INVENTORn HARRY G. EVERS ATTORNEY Patented Nov. 4, 1947 REMOTE-CONTROL SYSTEM Harry G. Evers, Newark, N. J., assignor to Automatic Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Original application August 3, 1944, Serial No. 547.955. Divided and this application July 16, 1945, Serial No. 605,419

7 Claims. 1

The present invention pertains to impulse transmitters for automatically transmitting codes, each consisting of a series of impulses, in response to the closing of corresponding control circuits.

The present case is a division of my copending application, Serial No. 547,955; filed August 3, 1944; entitled Remote control systems.

The principal object of the present invention is to provide an improved impulse transmitter and an associated register that will transmit codes in the same sequence in which the corresponding control circuits are closed even though they may both be closed before the impulse transmitter has started to transmit.

A further object of the invention is to provide an impulse transmitter and an associated register that will transmit codes in a predetermined sequence when the corresponding control circuits are closed simultaneously.

A feature of the invention is the provision of an improved impulse transmitter including a chain of counting relays wherein one of the counting relays is operated to select a code, the succeeding relays being sequentially operated to transmit the selected code, and wherein one of the counting relays is then reoperated and the cycle repeated without transmitting any code to provide a variable spacing interval between successive codes.

In the specific embodiment of the invention herein described the invention is used to control the flight of an airplane from a ground station or from a second airplane by means of a radio link. The invention has been illustrated by schematic diagrams comprising Figs. 1 to 4, in which:

Fig. 1 is a schematic diagram of the control device and the associated register relays,

Fig. 1A illustrates the construction of the control device,

Fig. 2 shows the automatic code sender,

Fig. 3 is a block diagram of the radio link,

Fig. 4 shows the control relays which are located in the controlled plane.

The control device I illustrated in Fig. 1A comprises a shaft I38 supported by and extending through a flexible rubber mounting I39 which normally holds the shaft I38 in a vertical, or neutral, position. One end of this shaft serves as handle and the opposite end carries a cam IOI. Four snap-action switches I03 to I66 are mounted around th cam and are spaced 90 apart. The flexible mounting permits movement of the cam from its neutral position so as to operate any one of the switches individually or so as to operate any two adjacent switches simultaneously. The handle of the control device simulates the control stick normally used to control the flight of an airplane, the movement of the handle to operate any of the fou switches corresponding to the movement of a control stick in an airplane to control the rudder and elevators.

The relay equipment shown at the right of the control device in Fig. 1 consists of two relay registers, each capable of storing one of two control signals and a release signal. One of these relay registers is associated with switches in the control device which are operated by upward or downward movement of the cam and the second relay register is associated with the remaining two switches which are operated by lateral movement of the cam. The purp o th s tw lay registers is to determine what code the automatic code sender should transmit and in the case of a series of codes to determine the sequence in which the series of codes are transmitted.

The automatic code sender and interval timer shown in Fig. 2 consists of a pair of pulse generating relays 201 and 208, a series of counting relays 210 to H4, start relays 204 and 285, spacing relays ZIJI and 203, and several auxiliary relays. Whenever the start relays are operated by the relay registers the pulse generating relays operate to generate impulses. The register relays also cause a particular one of the counting relays to operate. Ilhe impulses generated by the pulse generating relays cause the counting relays succeeding the particular counting relay operated by the register relays to be operated one at a time. When the last counting relay operates it stops the operation of the pulse generating relays. The number of impulses generated thus depends on the particular counting relay operated by the relay registers. The impulses are transmitted to the controlled plane simultaneously with the operation of th counting relays. At the conclusion of each series of impulses the spacing relays cause the pulse generating relays and the counting relays to go through another cycle of operations without transmitting any impulses to the controlled plane. This spacing interval serves two purposes, first it provides time for the control relays in the controlled plane to reset themselves after a series of impulses so as to be prepared for a second series, and secondly it provides for the operation of an apparatus unit in the controlled plane for a definit time interval in response to only a momentary operation of the corresponding switch in the control device.

The radio link, which serves as the control lays.

of the controlled plane through suitable gearin channel in this particular application of the invention, has been shown in block form in Fig. 3 as the details of this equipment form no part of the invention. Fig. 3 indicates that the radio frequency oscillator Edi and the audio frequency oscillator 3&2 used to modulate the :radio frequency carrier both controlled by the automatic code sender. This control may be effected by any of the numerous methods familiar to those versed in the art. Similarly any familiar method may be used for deriving a direct current from the audio signal in the receiver v283 of the controlled plane to operate a. relay.

The control relay circuit shown in Fig. 4 comprises an impulsing relay 42 I ,lock pulse relay 82, counting relays 535 to M5, pulse directin relay :33, slow release relays 4G4 and register relays M l to M4, and release relay H5. When the automatic code sender at the control station-operates it starts the radio frequency oscillator to generate the carrier wave and causes 'the audio frequency oscillator to operate intermittently in accordance with the code to be transmitted. The

carrier-wave with the audio signal superimposed on it is-transniitted' to the controlledplane W are the signal is demodulated and .the audio component is rectified vto'furnish a direct current-to the 'impulsing relay dill of 'Fig. 4, which is'thus caused to repeat the impulses to the counting relays. One of the counting relays is operated for each impulse received. At the end of the series of impulses a momentary circuit iscompleted, throueh contacts of the last counting relay-operated, to the corresponding register relay or .to the release relay. When a register relay is operated-by this momentary circuit it locks itself operated under the control of the release relay and closes an operating circuit to its corresponding apparatus unit. The register relay gremains operated until a release code is received,'which may not occur until other register relays have been operated. Each of the register relayscorresponds to one or" the switches in the control device, the objectbeing to operate the register trelays in accordance with the condition of the switches in thecontrol device. Whenever any of the switches in the control device -is released the release relay in Fig.4 is operated and it releases the register-re- If two switches in the control device have been operated and then only one is :released the release relay in Fig. awilloperate torrelease both of the-corresponding register relays in the controlled plane but the automatic code sender at the controllingstation will immediatelycause the re-operation of the register relay-in the controlled plane corresponding'to the switch which remains e 4 to control the position of the :rudder-and elevators and mechanical couplings. Limit switches may also be provided for-these motors to restrict the motion of the rudder and elevators within any desiredlimits.

The operation will nowbe described in greater detail with reference to the accompanying drawings. The operation of Figs. 1 and 2.may be'fol lowed conveniently if they areplaced side by side with Fig. 1 on the left. In Fig. l it will be seen :that for each of the four switches 183 to IE8 thereis provided .a co respond ng register relay Hi9, H2, 163 and H3, and'tnatza release relay H9 or H4 is provided for each pair of switches.

contacts l.

operator moves the handle of the control device so as to cause the cam li to operate switch 93, which causes the operation of relay m8 over an obvious circuit.

Relay its operates and closes its locking circuit through contacts US to contacts ll of relay .Hil, closes a circuit to the start relay 285 over lead 205A at contacts Hi3, prepares a circuit to relay H0 at contacts H3, prepares a circuit to relay ifil from lea i at contacts 523, and prepares a circuit to countin relay 213 over lead 213A from lead 22- at contacts E23. Relay 295 operated, closes a circuit to relay at contacts 215, prepares a locking circuit for the counting relays at contacts 257, closes a circuit at con- .tacts'2l8 to connect leads 3M and 355 to start the radio frequency cscillatcr and closes circuits to relays and at co. tacts 2'59. Thecircuit forrelay be traced fr in battery at contacts 253 through contacts 230 of relay 2P3, contacts 22! of relay 29 thrcughrQlay-LZQE to ground at contacts 222 of relay 2538. The oilcuit for relay may be tracedfrom battery at contacts 25;; thr h contacts 223 of relay 20 lead 26:), contacts 9.. of relay H3, contacts 122 of relay H 8, contacts 123 of relay 285,1ead2'l3A, contacts 225 of relay 2M to relay 21,3. Relay 206 operates, closes its locking circuit at contacts 225, and connects leads and 36? at contacts 228 to start the audio frequency oscillatorZGZ. Relay Z-E'B-operateacleses its locking circuit at contacts to contacts 257 of relay 235, and prepares a circuit to the succeeding counting relay 2.!2 at contacts 228. Relay 26!; operates, opens theoperating circuit for relay and closes a cult to relay 2% at contacts 22!, closes a second locking circuit for relay 159 over lead lOSA at contacts prepares locking circuits for relays 2 2 and .225 at contacts 235i and prepares a circuit for elay l0] over lead i 553A at contacts 23!.

Relay 268 operates and closes a circuit to relay Relay 201 operates and opens the circuit to relay 208 at contacts 232. Relay 258 restores and opens the circuit to relay 201 which restores and re-closes the circuit to relay 233. This cycle or" operations continues as long as battery is available from contacts 2| 9 of relay 2 .25 to operate relay 208. The release times of relays 2i and 228 can be adjusted by means of adjustable shunting resistors 233 and 234, respectively, to secure the desired speed of operation and optimum per cent closure time of the contacts of relay 208. The first operation of relay 'ZGS-opens the circuit to relay 205 at contacts 2.22, closes a multiple circuit to leads 306 and 301 at contacts 2'83, and closes a circuit to relay H2 at contacts through contacts'238 of relay 209 and contacts 228 of relay 2|3. Relay 206 re- 0 stores. Relay 252 operates, closes its locking circuit at contacts 236, prepares a circuit to relay 2! i at contacts and prepares a circuit to pulse directing relay 283 at contacts 238. The first restoration of relay 2G8 opens the circuit between leads 3'5 and at contacts 263 to interrupt the operation of the audio frequency oscillator 302, opens the operating circuit to relay 2| 2 and closes an obvious circuit to relay 289 at contacts 235. Pulse directing relay 233 operates, prepares a circuit forrela L2H at contacts 236 through contacts 231 of relay 2I2, and closes its own locking circuit at contacts 239. The second operation of relay 208 closes a multiple circuit to relay 209 at contacts 222, closes a circuit to relay 2 II at contacts 235, and recloses the circuit between leads 306 and 301 at contacts 263. Relay 2H operates, closes its locking circuit at contacts 240, prepares a circuit to relay 2I0 at contacts MI, and opens the operating circuit to relay 209 at contacts 242. The second restoration of relay 208 opens the circuit to relay 209 at contact 222, opens the operating circuit to relay 2II at contacts 235, and again interrupts the operation of the audio frequency oscillator at contacts 263. Relay 209 restores and prepares a circuit to relay 2I0 through contacts 24I of relay 2| I. The third operation of relay 208 closes the circuit to relay 2I0 at contacts 235 and closes the circuit to the audio frequency oscillator 302 at contacts 263 for the third time. Relay 2I0 operates, closes its locking circuit at contacts 243, prepares a circuit to relay 202 at contacts 244, and opens a second point in the circuit to relay 208 at contacts 220 to prevent any further cycling of relays 201 and 208. When relay 208 restores for the third time it closes a circuit to relay 202 at contacts 235 through contacts 244 of relay 2I0, and opens the circuit to the audio frequency oscillator 302 at contacts 263. Relay 202 operates, opens the circuit to relay 205 at contacts 245, closes its locking circuit at contacts 246, and prepares a circuit fOr relay I01 over lead II5A at contacts 241. Relay 205 restores, opens the circuit to the radio frequency oscillator 30I at contacts 2I8, opens the circuit to relay 204 at contacts 2I6, opens the locking circuit to the counting relays at contacts 2I1, and closes a circuit to relay I01 at contacts 248. This last circuit may be traced from contacts 248 through contacts 241 of relay 202, contacts 23I of relay 204, contacts 249 of relay 20I, contacts 250 of relay 203, contacts 25I of relay 2I5, lead II5A, contacts I20 of relay I09 to relay I01. Counting relays 2I0, 2H, M2, and 2I3 restore. Relay I01 operates, opens the operating circuit for relay I09 at contacts I24, opens the first locking circuit for relay I09 at contacts II 1, prepares a second circuit path to relay H at contacts I25, and closes its locking circuit at contacts I26 to contacts I21 of relay H5. Relay 204 restores, opens the second locking circuit for relay I09 over lead I08A at contacts 229, opens the locking circuit for relay 202 at contacts 230, opens the operating circult to relay I01 over lead IIA and closes the circuit to relay 20I at contacts 23I. The last circuit may be traced from contacts 248 of relay 205, through contacts 241 of relay 202, contacts 23I of relay 204, contacts 252 of relay 203 to rela 20L Relay I09 restores and prepares a circuit to relay H5 from lead II5A. Relay 20I operates, opens the marking lead 200 to the register relays of Fig. 1 and prepares a circuit to relay 2I3 at contacts 223, prepares a circuit to relay 205 at contacts 253, prepares a circuit to relay 203 at contacts 249, closes its locking circuit at contacts 254 to contacts 255 of relay 203, and opens points in the circuits between leads 306 and 301 and between leads 304 and 305 at contacts 256 and 251 respectively, to prevent operation of the radio equipment during the spacing interval. Relay 202 restores, opens the operating circuit to relay 20! at contacts 241, and closes a circuit to relay 205 at contacts 245 through contacts 253 of relay 20L Relays 205, 204, 2I3, 206, 208, 201, 2I2, 2H, 2 I0, and 209 operate in the same manner aspreviously described except that the operating circuit to relay 2I3 is now through contacts 223 of relay 20I instead of through contacts of the relays in Fig. l. The operation of relay 202 and subsequent release of relay 205 after this second cycle of operations closes a circuit to relay 203 from contacts 248 of relay 205, through contacts 241 of relay 202, contacts 23I of relay 204, and contacts 249 of relay 20I. Relay 203 operates, closes its locking circuit at contacts 258, and opens the locking circuit to relay 20I at contacts 255. Relay 20I restores and opens the operating circuit to relay 203 at contacts 249. Relay 204 restores and opens the lockin circuit to relay 202 at contacts 230, Relay 202 restores and opens the locking circuit to relay 203 at contacts 241. Relay 203 restores. All relays are now released except relay I01 which remains locked to contacts I21 of relay H5.

The operation of the radio link and the control relays shown in Fig. 4 will now be described. It will be recalled that during the operation of the automatic code sender of Fig. 2 that leads 304 and 305 were connected during the first cycle of operations and that during this same cycle of operations leads 306 and 301 were closed three times during successive operation of relay 208. The closure of leads 304 and 305 caused the radio transmitter of Fig. 3 to produce a high frequency carrier which is radiated by aerial 308 and received through antenna 309 of the receiver 303 in the controlled plane. The reception of this carrier does not produce any output on lead 40 IA as yet. However, each time that leads 306 and 301 are closed the audio frequency oscillator 302 produces an audio signal which is used to modulate the high frequency carrier, The receiver 303 demodulates the modulated carrier to reproduce the audio signal. A direct voltage is then derived from the audio signal and is used to operate a sensitive relay which is included in the receiver. Contacts on this sensitive relay are used to close a circuit between leads 40IA and battery. By this means pulses of direct current are applied to lead 40IA corresponding to the operations of relay 208 of the automatic code sender.

Referring now to Fig. 4, each pulse of current over lead 40IA causes relay 40I to operate. On the first pulse relay 40I operates, closes its locking circuit at contacts 4I6, closes a circuit to relay 404 at contacts M1, and closes a circuit to relay M0 at contacts 4I8 through contacts 4I9 of relay 403, contacts 420 of relay 401, and contacts 42I of relay 409. A circuit to lock pulse rela 402 is also closed at contacts 4I8 of relay 40I. By properl proportioning the resistance and number of turns used in the coil winding of relay 402 it can be made slower to operate than any of the counting relays 406 to- M0, thus insuring that relay 40I will remain looked through contacts 422 of relay 402 until the counting relay has operated when the pulse of current on lead 40IA is of short duration. Relay 4I0 operates, prepares its locking circuit at contacts 423, prepares a circuit to relay 409 at contacts 424, and prepares a circuit to relay 403 at contacts 425. Relay 402 operates, opens the locking circuit to relay 40! and closes a multiple circuit to relay 404 at contacts 422. Relay 404 Operates, prepares a bleeder circuit to itself through resister 432 at contacts 426, closes a circuit to rela 405 at contacts 421, and closes a locking circuit for the counting relays at contacts 428, It should be noted here that the first impulse in each series produced by the automatic code sender is longer than the remaining impulse in order to insure that relay 404 has sufficient time to operate and prepare the locking circuit for the counting relays, Relay 405 operates and closes a multiple circuit for locking the counting relays at contacts 429. At the end of the first pulse of direct current on lead 40IA the circuit to relay 40I is opened. Relay 40I restores, opens the operating circuit to relay 404 t contacts 4E1, opens the operating circuits to relays 402 and 420 at contacts M0, and closes a circuit to relay 403 at contacts M8 through contacts430 of relay 409 and contacts 425 of relay M0. The circuit to relay- 402 is maintained through contacts 4E0 of relay 403, contacts 420 .of relay401, contacts 42! of relay 409, contacts 423 of relay H0, and contacts 420 of relay 404. Relay 403 operates, closes its lockin circuit at contacts 43!, and opens the holdin circuit for relay 402 and prepares a circiut to relay 400 at contacts M0. Relay-402 restores, opens the holding circuit to relay and prepares the locking circuit to relay 40L The circuit to relay 404 is now completed through contacts 425 and resistor 432. Resistor is high enough so that relay 404 cannot remain operated in series with this resistance indefinitely, but the release time of the relay is considerably increased by this bleeder circuit to insure its continued operation during the series of impulses.

Relay 40! operates on the second pulse of current over lead 401A, closes its locking circuit, closes a direct circuit to relay 404, closes .aoircuit t relay 402, and closes a circuit to relay 409 at contacts4l8 through contacts MS of relay 403, contacts-433 of relay-408, and contacts 424 of relay'4I0, and closes a holding circuit to relay 403 at contacts 434. Relay 409 operates, closes its locking circuit at contacts 435, prepares a circuit torelay 408 at contacts 42I, and opens the operating circuit to relay 403 at contacts 430. Relay 402 operates, opens the locking circuit to relay .-40I..and:closes a multiple circuit to relay 404 at contacts 422. Relay 40I restores either when its locking circuit is opened or when the pulse of current on lead 40IA ceases, depending on which event occurs last. When it restores it opens the holding circuit for relay 403 at contacts 434.

Relay 403 restores, opens the holding circuitfor relay .402and prepares a circuit for relay 408 at contacts 4I9. Relay 402 restores. The third pulse of current over lead 40 IA operates relay 40I 'forthethird time causing the operation of relays .408 and 402. The operation of relay 408 prepares a circuit to relay 403 at contacts 430 which is completed at contacts -4I3 of relay 40! when it restores for the third time. Relay 403 then operates and opens the holding circuit to relay 402 at contacts 4I9 which releases and opens the holding-circuit to relay 404 at contact 422. At this time relays 403,404, 405, 408, 409, and M are operated. Relay'404 restores, opens the circuit to relay 405 and closes a circuit to relay M3 at contacts 421 through contacts 431 of relay 405, contacts 438 of relay 406, contacts 439 of relay 401, and contacts 440 of relay 400. Relay 4l3 operates, closes its locking circuit at contacts 44I, prepares a locking circuit for relay M5 at contacts 442, and closes a circuit to motor M6 at contacts 443. Relay 405 restores, opens the operating circuit to relay M3 at contacts 431 and opens the locking circuit for the counting relays at contacts 429. Counting relays 408, 409, and M0 .restore opening the circuit to relay 403 at contacts 436 causing it to restore.

All of the control relays are now normal with theexceptionof relay 3. The motor 6 cperates to turn the rudder of the controlled plane .so as to direct the plane to the left. The motor the release of relay 4I3 as will presently be described. The arc through which the rudder moves is thus determined by the length of time that the control device I00 is held in the operated position. Since it is diflicult for an operator to estimate short time intervals the automatic code sender is arranged to provide a predetermined minimum time interval between operation and release signals so that the rudder can be moved through a small arc in response to only a momentary operation of the control de- -vice I00. This minimum time interval is introduced by the second cycle of operations of the pulse generating and counting relays of the code sender that was previously described. The duration of this time interval is determined by which one of the leads 2IIA to 2I-4A that the make contact of contacts 223 is connected to as indicated by the dotted lines in Fig. 2.

The operation which brings about the release of relay 4I3 and'thus stops the operation of motor M6 in the event'that the rudder hasnot yet reached the limit of its travel will now be described. It will be remembered from the previous description that all of the equipment in Figs. 1 and 2 is at normal except switch I03 and relay I01. When the control device is restored to the neutral position a circuit is closed to relay H0 at switch I03 through switch I05 and contacts I25of relay I01. Relay IIO operates, closes its locking circuit at contacts I28, closes a circuit to-relay 205 over lead 205A at contactsl29, and prepares a circuit to relay 2II over lead 2IIA from lead 200. Relays 204 to 200 operate the same as'previously described except that the operation of relay 205 closes a circuit to relay .2I I at contacts 2I9 instead of to relay 2I3 causing the operation of relay 2| I. This circuit may be traced from contacts 2| 9 through contacts 223 of relay 20I, lead 200, contacts I2l ofrelay II3, contacts I22 of relay I08, contacts I23 of relay I09, contacts I30 of relay II2, contacts I.3I of relay H0, and over lead 2IIA to relay 2| I. Thus the first operation of relay 208 brings about the operation of counting relay'2l0 which prevents any further operation of relay 208 and thus permits only a single pulse of audio frequency modulation on the radio frequency carrier produced by the oscillator 30I. When relay 205 restores following the operation of relay 202, as previously described, a circuit is closed to relay I I5 at contacts 248 of relay 205 through contacts '241 of relay 202, contacts 23I of relay 204, contacts 249 of relay 20I, contacts 250 of relay 203, contacts 25I of 'relay 2I'5, lead II5A, contacts I20 of relay I09, contacts I32 of relay I08, contacts I33 of relay H2, and contacts I34 of relay H3. Relay I I5 operates, closes its lockin circuits at contacts I35 to lead I I5B, opens the locking circuit to relay H0 at contacts I30, and opens the locking circuit to relay I01 at contacts I21.

Relay I01 restores and opens the operating circuit to relay H0 at contacts I25 causing it to restore. Relay 204 restores, closes a circuit to relay 20| causing it to operate and opens the locking circuit to relay 202. Relay 202 restores, closes a circuit to relay 205, and opens the locking circuit to relay H5 at contacts 241. Relay II5 restores completing the restoration of Fig. l to normal. Relay 205 operates and causes the automatic code sender to go through a second cycle of operations to produce a spacing interval in precisely the same manner previously described. The single audio frequency pulse applied to the carrier by the operation of the automatic code sender causes a single pulse of direct current to be received over lead 40IA of Fig. 4 to operate relay 40I. Relays MI, 402, 404, 405, and M again operate as p eviously descri ed. At the end of the pulse of current over lead 40I A relay 40I restores and closes a circuit to relay 403 at contacts 4I8 through contacts 430 of relay 409 and contacts 425 of relay 4I0. Relay 403 operates and opens the holding circuit to relay 402 at contacts 4I9 which restores and opens the holding circuit to relay 404 at contacts 422. Relay 404 restores, opens the circuit to relay 405 and closes a circuit to release relay M5 at contacts 421 through contacts 438 of relay 406, contacts 439 of relay 401, contacts 440 of relay 408, contacts 444 of relay 409, and contacts 445 of relay 4I0. Relay 4I5 operates, closes its locking circuit at contacts 445, and opens the locking circuit to register relay 4I3 at contacts 441. Relay 4I3 restores, opens the locking circuit to relay M5 at contacts 442, and opens the circuit to motor M6 at contacts 443, if this circuit has not yet been opened by the limit switch. Relay 405 restores, opens the operating circuit to relay M5 at contacts 431, and opens the locking circuit to relay M0 at contacts 429. Relay 4I5 restores. Relay 4I0 restores and opens the circuit to relay 403 at contacts 425 causing it to restore. All relays in the system are now at normal.

It will now be apparent that if the control device was operated so as to cause a momentary operation of switch I03 the operation would still be exactly the same except that relay IIO would be operated early in the cycle and would cause the automatic code sender to send the release code, consisting of a single impulse, immediately after the spacing interval. The motor 416 would then be operated for a length of time equal to the spacin interval. Such a momentary operation of the control device may be repeated as often as desired to cause movement of the rudder of the controlled plane in discrete steps.

When the control device I00 is operated so as to cause cam IOI to operate switch I05 the operation is similar to that described for the peration of switch I03 except that relay I08 is operated in place of relay I09 and it causes counting relay 2I2 to be operated in place of relay 2I3 when relay 205 operates. As a result the first operation of relay 208 operate relay 2 and the second operation operates relay 2I0 to stop futher impulsing. Two pulses of audio frequency modulation are thus applied to the carrier to cause two operations of relay 40I in the controlled plane. These two operations of relay 40I cause counting relays 40I and 409 to be operated so that when relay 404 restores a circuit is completed to register relay 4I4 through contacts 444 of relay 409. The operation of relay 4I4 completes a circuit to motor 4I6 through a separate field winding causing it to run in the reverse direction to move the rudder so as to direct the controlled plane to the right. The release of relay 4I4 is brought about by the operation of relay M5 the same as previously described 10 when the control device I00 is returned to neutral.

In a similar manner the operation of the control device to the up or down positions cause the automatic code sender to deliver a series of four or five impulses to the audio frequency oscillator 302 in response to the operation of switches I04 or I06 respectively. The operation of relays III to II4 which are associated with these switches is the same as that of relays I01 to H0 except that a different one of the counting relays in the code sender is made to operate first. When relay I I 2 is operated a circuit is prepared through contacts I30 and lead 2I4A to operate relay 2I4 as soon as relay 205 operates. An impulse is thus produced for each of the remaining counting relays 2I0 to 2I3. When relay H3 is operated none of the counting relays is operated by the operation of relay 205 and consequently five impulses will be produced by the automatic code sender. The first impulse will operate relay 2I4 and the fifth impulse will operate relay 2I0. In either case relay 2I4 will be operated and will close a circuit to relay 2I5 at contact 259. Relay 2I5 upon operating prepares a circuit to operate relay 2I3 on the succeeding operation of relay 208 at contacts 250, closes its locking circuit at contacts 26I, and prepares a circuit to operate relay III over lead IIIA at contacts 25! at the end of the series of impulses. When four impulses are transmitted relay 401 will be the last counting relay operated in Fig. 4 and will cause a circuit to be closed to register relay 4I2 through contacts 439 upon the release of relay 404 at the end of the series. If five impulses are transmitted relay 400 will also be operated causing the release of relay 404 to close a circuit to register relay M I. Relay 406 performs an extra function by opening the holding circuits for relays MI and 404 at contacts 448. This is a precaution to prevent a lockup from occurring if more than five impulses are delivered to relay 40! through a false operation. The operation of relays 4II and M2 control the operation of motor 4I1 to move the elevators of the controlled plane in the same manner as described for motor M5 in connection with the rudder.

Simultaneous operation of relays MI and 4|?! or of relays M3 and 4I4 is prevented by the relay registers associated with the control device. For example, if cam MI is moved so to co erate switch I04 and then is immediately moved to operate switch I03 both relays I03 and I50 will be operated. Relay I I0 will also become of erated during the time that the cam is being shifted from switch I 05 to switch I03. In this case a code consisting of two impulse will first be transmitted to operate relay 4I4. The operation of relay I01 and the release of relay 204 at the end of the first cycle of operations of the automatic code sender will release both relays I08 and I99. Relay IIO remains locked to contacts I36 of relay H5 and causes the code sender to send a release code consisting of one impulse which causes the release of relay 454. The operation of relay H5 at the end of this cycle of operations of the code sender releases relays IIli and H0. The release of relay I01 recloses the circuit to relay I09 from switch I 03 allowing it to reoperate and cause the code sender to transmita code consisting of three impulses to bring about the operation of relay 4I3. Although this sequence of operations takes a considerable time to describe it actually occurs in a very brief interval inasmuch as it has been found entirely practical to operate the equipment ata speed of thirty-five impulses per second and the longest single code which need be transmitted consists of five impulses.

The relay registers of Fig. 1 also control the sequence in which codes are transmitted when the control device is operated so as to actuate two adjacent switches simultaneously. This oc curs when it is desired to cause the controlled plane to climb or dive and to turn at the same time. If it is desired that the controlled plane climb and turn left at the same time the control device tee is operated so that cam I] is moved to operate switches I63 and I54. Relays I09 and H2 will both be operated. The code for a, left turn will be sent first due to marking of the counting relays by contacts I23 of relay I69. Relay lS'i will be operated after this code has been transmitted and relay 09 will be released when its locking circuit over lead [08A is opened by the release of relay 284. After the spacing interval has been timed by the code sender the code corresponding to a climb will be transmitted due to the marking of the counting relays by contacts 33 of relay H2. At the end of this second code relay l M will be operated and relay I 12 will be released. The transmission of this second code brings about the operation of relay H2. Both motors H6 and All will now be operating simultaneously. If the control device is returned to release relays H9 and I will be operated and will cause the code sender to send the release code to operate relay M5, thus releasing relays H2 and M3 to stop both motors. However, if it is desired to stop only one motor the control device may be operated to move cam Hit from the position where both switches I03 and IE4 are operated to a position where only one of the switches is operated without releasing the switch which remains operated. For example, in the above case the cam can be moved so that switch I93 remains operated but switch IE4 is released. Relay H4 will then be operated through switches [06 and EM and through contacts l3? of relay Ill. The operation of relay H4 causes the code sender .to transmit a release code which will bring about the operation of relay M5 and consequent release of relays M2 and M3. Relay H5 will be operated after this code is sent and will cause the release of relays I51, HI, and H4. The release of relay l9? re-closes the circuit to relay I99 from switch I83 which causes the code sender to retransmit the code for a left turn and thus causes the immediate re-operation of relay 413. The operation of motor H6 is thus only momentarily interrupted and the operation of motor 411 is stopped completely.

In the preceding paragraph it was assumed that switches i533 and 04 were operated simultaneously. This would cause the coded signal for a left turn to be transmitted first due to the preference given to this code in the marking chain. The sequence can be reversed by causing switch 8 3 to be operated slightly ahead of switch 153. This will permit relays H2 and 285 to become operated and thus cause the operation of relay 224 before relay I99 operates to interrupt the operating circuit for relay 214 at contacts I23. The

peration of relay I89 at this time will not alter the operation or" the counting relays because the marking circuit extending from lead 2% through contacts 523 of relay I09 to lead ZIEA is opened at contacts 22:. of relay 2M. Contacts 262 serve a similar purpose when relay 1 GB is operated during the time that the code sender is transmitting 12 an up or down signal. Th code signal are thus transmitted in the same sequence that the control switches are operated in.

It will also be apparent from the preceding description that the cam IOI can be moved to operate one of the switches, say 104, to bring about the operation of the corresponding register relay 412, in the controlled plane and may then be moved so as to operate one of the adjacent switches, say I03, without releasing the first switch operated. This will cause the operation of the corresponding register relay 413, without releasing relay 4112.

While the invention has been described in connec-tion with a radio link it is obvious that it may be used without such a link in other applications. If the radio link is omitted lead 306 of Fig. 2 is connected to lead IA of Fig. 4 and lead 39'! is connected to battery of Fig. 4. Leads 304 and 305 are not required for this mode of operation.

Having described and illustrated the invention what is considered new and is desired to secure by Letters Patent is pointed out in the subjoined claims.

What is claimed is:

1. In combination with a code transmitter comprising a chain of counting relays and impulsing means therefor, a plurality of register relays each being associated with difierent ones ofsaid counting relays, means for at times operating a plurality .of said register relays simultaneously, means responsive to the operation of said register relays causing the operation of one of the associated countin relays and causing the succeeding counting relays to be operated in sequence by said impulsing means, and means controlled by said counting relays causing the release of the particular register relay that is associated with the counting relay first operated.

2. In combination with a code transmitter comprising a chain of counting relays and impulsing means therefor, a plurality of register relays each being associated with different ones Of aid o in r la a r t mea s r o rat one of said register relays, circuit arrangements causing the operation of the counting relay associated with said one register relay in response to its operation and causing the succeeding counting relays to' be 1 operated in sequence by said impulsingmeans, and a second means controlled y Med c -s c e di cou t n 'fi 'y causme th re e e of S i n is e relay and t pperated counting relays.

"3. In combination with a code transmitter as claimed in elaim 2, a third means for operating a s c of ai eg rela said e arrangements causing the operation of the counti is la a so iate it sa d s co e t elay in re o s to it at o a cau the ose d ns u t n e a to be o r t i sequence by said impulsing means, and a fourth means controlled by said pne of the succeeding counting relays causing the release of said second means.

4. A code transmitter comprising a chain of relays and normally inactive impulsing means thereior, a first means for operating any one of the relays in said chain and for starting said impulsing means, circuit arrangements causing the relays in the chain succeeding said one relay to be energized in sequence by said impulsing a se ond means to to n t operation of said impulsing means when a particular relay in the chain is operated, an auxiliary circuit over which impulses are transmitted by said impulsing means during the above cycle of operations, a third means responsive to the completion of said cycle of operations for operating a particular one of the relays in said chain and for restarting said impulsing means, said circuit arrangements causing the relays in the chain succeeding said particular relay to be energized in sequence by said impulsing means, said second means stopping the operation of said impulsing means when said particular relay is again operated, said third means preventing transmission of impulses over said auxiliary circuit by said impulsing means during the second cycle of operations.

5. A code transmitter as claimed in claim 4 including strapping means for varying the connections of said relays to said third means to thereby determine which particular relay will be operated bysaid third means, thereby at times causing diiferent ones of the relays in said chain to be operated by said third means, whereby the duration of said second cycle of operations may be varied.

6. A code transmitter comprising a chain of relays and normally inactive impulsing means therefor, a first means for operating any one of the relays in said chain and for starting said impulsing means, circuit arrangements causing the relays in the chain succeeding said one relay to be energized in sequence by said impulsing means, a second means for stopping the operation of said impulsing means when a particular relay in the chain is operated, a third means responsive to the completion of the above cycle of operations for operating a particular one of the relays in said chain and for restarting said impulsing means, said circuit arrangements causing the relays in the chain succeeding said particular relay to be energized in sequence by said impulsing means, said second means stopping the operation or said impulsing means when said particular relay is again operated, said third means disabling said first means during the second cycle of operations.

7. A code transmitter as claimed in claim 6 including strapping means for changing the connections of said relays to said third means, thereby at times causin different ones of the relays in said chain to be operated by said third means, whereby the duration of said second cycle of operations may be varied.

HARRY G. EVERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Number 

